ISO/IEC 20968:2002 specifies the set of definitions, conventions and activities of the MkII FPA Functional Size Measurement Method.

The method can be used to measure the functional size of any software application that can be described in terms of logical transactions, each comprising an input, process and output component. The sizing rules were designed to apply to application software from the domain of business information systems, where the processing component of each transaction tends to be dominated by considerations of the storage or retrieval of data.

The method may be applicable to software from other domains, but the user should note that the sizing rules do not take into account contributions to size such as from complex algorithms as typically found in scientific and engineering software, nor do the rules specifically take into account real-time requirements

MK II FPA is independent of the project management method to be used and of the development method employed. It is a measure of the logical, business requirements, independent of how they are implemented.